1. Field
The apparatus is in the field of apparatus for sensing and measuring pressure in closed containers, specifically tubes and pipes. More specifically it is in the field of such apparatus which is used externally to the containers, pipes and tubes and, still more specifically, the field is limited to apparatus which detects changes in pressure in a particular tube containing fluid under pressure.
2. Prior Art
The patents listed below constitute a sampling of the prior art in the specific field.
______________________________________ 3,163,529 4,290,311 3,603,152 4,321,833 3,898,885 4,391,147 3,965,745 4,404,854 4,174,637 4,646,563 Japanese: 55-96432(A) ______________________________________
In addition there is commercially available prior art apparatus not known to be patented. A diligent, comprehensive review of the commercially available prior art and a preliminary search of patented prior art did not lead to apparatus which solved the problem addressed by the subject invention. That problem was the need to quickly and easily detect changes in pressure in any particular tube in a cluster of tubes. An example of such a cluster of tubes is the tubing exposed in the wheel well of a modern commercial airplane. Analyzing (i.e. troubleshooting) the hydraulic systems which the tubing serve is greatly facilitated by being able to detect which tubes are pressurized or not without disrupting the function of the tubing or the systems they serve. Therefore, the prime objective of the subject invention was to provide apparatus which can detect changes in pressure of the fluid in a conduit without interfering with the function of the conduit. Other objectives were that the apparatus be compact and usable on any one of a cluster of conduits; i.e. be able, for example, to fit onto one tube mounted close to one or more other tubes and in a range of diameters. Another objective was that the apparatus be mechanically self-supporting once it is installed on a conduit.